The present invention relates generally to a structure of an insole, and more particularly to an insole that is implemented with strong elasticity and excellent retention properties and is inserted into an article of footwear to provide a user of the article of footwear with superior cushioning and comfort.
Many activities pertaining to daily lives generate shock to the human feet. Such activities include “normal” walking while commuting or shopping, jogging, training athletically, physiotherapeutic rehabilitation by persons suffering from injuries or handicaps, and many other situations. Over an extended period of time, such shock to the human feet may cause injury. In order to reduce injury brought about from such shock, shoe insoles, which are materials cut into the shape of a human foot and inserted into an article of footwear, are designed with good shock absorption properties to provide the human feet with more cushioning and support.
To obtain good shock absorption properties, some existing insole designs provide a plurality of flexible layers. Each of these layers is typically made of a separate material, a unique slope, a unique thickness, as well as other factors. Inventions related to insoles and shoes are common. However, none of the prior art devices disclose the unique features of the present invention.
In U.S. Pat. No. 5,809,665, Suenaga disclosed a shock absorbing and humidity reducing insole for a shoe having a thickness that increases gradually from an arch portion toward a heel portion. The insole comprises a sealed chamber defined by a recess and several grooves that are formed within the insole to provide shock buffering effect when some ventilation holes are covered by user's foot during movement.
In U.S. Pat. No. 4,999,931, Vermeulen disclosed a shock absorber which may be used as an insole or as a midsole for an article of footwear. The shock absorber is made of a rubber-type material such as a multi-cell membrane which may be embedded in a flexible envelope or which may be used itself as a one-piece multi-cell membrane insole or midsole.
U.S. Pat. No. 5,675,914 discloses an air circulating sole structure with a layer of moldable material, a system of intersecting channels, and a shock absorbing material. In another example, U.S. Pat. No. 6,968,637 provides a sole structure having a plurality of semi-rigid and substantially parallel stabilizing members having a plurality of stiffness and movable elements relative to each other. In yet another example, U.S. Pat. No. 6,763,611 provides a sole structure with a lattice structure, which attenuates and distributes ground reaction forces by providing a plurality of connectors coupled with a plurality of masses. In yet another example, U.S. Pat. No. 6,675,501 provides a sole structure having at least three layers further having variable extensions, and made of different materials with variable density ratings. In yet another example, U.S. Pat. No. 4,055,699 provides a four-layer sole with a cross-linked polyethylene layer and a polyethylene terephthalate sheet.
These conventional insoles provide various means to provide shock absorption and protection, but because they require utilizing foamed or foamed-like material for providing shock absorption, they are more prone to material fatigue over time, which may result in the insole's inability to retain its shape and provide the necessary cushioning and perform shock absorption. Simpler insole designs such as U.S. Pat. No. 3,253,601 exist, but they are not effective in providing shock absorption.
Desirable in the art of shoe insole designs is a simple shoe insole with an ability to retain its shape that may be inserted within any shoe commonly available in the market to provide a human foot with superior comfort and support.